Comparison of a 0.55 T dental-dedicated magnetic resonance imaging system with a 1.5 T system in evaluation of the temporomandibular joint regarding subjective image quality assessment and rater agreement.

OBJECTIVE

We aimed to compare subjective assessment of image quality and rater agreement of magnetic resonance (MR) images of the temporomandibular joint (TMJ) acquired with dental-dedicated 0.55 T and clinical 1.5 T magnetic field strengths.

STUDY DESIGN

Six blinded raters evaluated randomized TMJ MR images from 5 healthy participants imaged with 3 pulse sequences on 2 scanners: a 0.55 T system using a custom-built surface coil for dental-dedicated applications and a clinical 1.5 T system using a standard head/neck coil. TMJ anatomy and image quality parameters were assessed using a three-point scale (0 = unacceptable, 1 = acceptable, and 2 = excellent). Data was pooled across participants, pulse sequences, and sides. Kappa coefficients were calculated for intra- and inter-rater agreement. Chi-square tests were applied to explore differences between scanners. Significance was established at P<0.05.

RESULTS

Four different raters preferred 0.55 T images for visualizing hard and/or soft tissue anatomy (P≤.02). One rater preferred the 0.55 T system regarding contrast. No other differences were detected regarding qualitative ratings. Kappa values for intra-rater agreement ranged from 0.49 to 0.70 for 0.55 T images and 0.42 to 0.71 for 1.5 T images. Inter-rater kappa values ranged from 0.02 to 0.29 for 0.55 T images and 0.02 to 0.23 for 1.5 T images.

CONCLUSIONS

Images from the two systems were rated similarly. Further research is needed to assess diagnostic performance in patients.